JP2000322870A - Magnetic disk apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an improved structure of a shroud capable of decreasing a fluid force to be generated by rotation of a disk and reducing power consumption that tends to increase due to disk flattering or fluid disturbance. SOLUTION: In a magnetic disk apparatus comprising a plurality of disks 15, 16 a head for performing recording and reproduction of information for the disks 15, 16, and a carriage for supporting the head, a shroud 10 for smoothing an air flow in a disk circumferential direction to be generated by rotation of the disks is provided so as to surround an outer periphery of the disks. The shroud 10 is provided with teeth 22 on its inner peripheral surface so that the respective teeth 22 are inserted into gaps between the adjacent disks from the outermost periphery of the disks toward the inner positions of the gaps. Furthermore, the shroud 10 is provided with an opening section for a moving action of the carriage. A shroud assisting section for covering the opening section is formed along the circumferential direction of the disks and attached to the shroud.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording apparatus for reading and writing information by positioning a recording head on a track of a rotary storage medium and reducing the exciting force of a swirling fluid generated with the rotation of the disk. Also, the present invention relates to a magnetic disk drive that reduces power consumption and achieves high precision positioning and low power consumption.

[0002]

2. Description of the Related Art FIG. 11 schematically shows a shroud shape in a magnetic disk drive. In FIG. 11, reference numeral 15 denotes a disk for recording information, which is rotated by a spindle motor 18. The wall 10 provided so as to surround the outer periphery of the disk 15 is a shroud. The shroud serves to smooth the circumferential flow caused by the rotation of the disk 15.

[0003] It has been studied in the past that if there is no shroud, the turbulence of the swirling flow due to the rotation of the disk increases, and the disk flutter increases. In FIG. 11, 32 is a head suspension, 31 is a carriage arm for supporting the head suspension, and 33 is a voice coil motor for positioning the head.

FIG. 12 shows an air flow pattern caused by rotation of a disk in a magnetic disk drive. In FIG. 12, 10 is a shroud, 15 is a disk, and 30 is an air flow pattern generated by rotation of the disk. This flow pattern meanders in the region between the disk periphery and the shroud due to centrifugal force. The difference in the pressure distribution generated by the meandering flow between the upper and lower surfaces of the disk is the main excitation force of the disk flutter and also contributes to an increase in power consumption.

In order to reduce the fluid excitation generated as the disk rotates as described above, in the prior art,
A rectifying plate is inserted between the disks (a rectangular plate is inserted from an outer peripheral side of the disk at an appropriate position between the disks to reduce the flutter amplitude of the disk), or a groove is formed on the shroud surface. Methods such as moving the turning point of the airflow from the inner circumference to the outer circumference away from the outer circumference of the disk have been performed.

[0006] Recently, measures have been taken to reduce the disk size.

[0007]

The conventional method of inserting the current plate between the disks is effective in reducing the disk flutter, but has the problem of increasing power consumption.

[0008] In addition, using a disk with a small diameter
Although the rigidity of the disk is increased, which is effective in suppressing disk vibration, there is a problem that the data area is reduced, so that it is not suitable for increasing the storage capacity.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a magnetic disk drive in which a region where a fluid force is generated is restricted to a portion in the inner circumferential direction of the disk, and the same effect as reducing the disk diameter can be obtained.

[0010]

In order to solve the above-mentioned problems, the present invention mainly employs the following configuration. A magnetic disk device comprising: a plurality of disks serving as information media; a spindle motor for rotating the disk; a head for recording and reproducing information on the disk; and a carriage for supporting the head. A shroud is provided around the outer periphery of the disk so as to smooth the induced air flow in the circumferential direction of the disk. A magnetic disk device inserted between the disks so as to be inserted.

[0011] Further, a plurality of disks as information media,
In a magnetic disk device including a spindle motor for rotating the disk, a head for recording and reproducing information on the disk, and a carriage for supporting the head, the airflow in the disk circumferential direction caused by the rotation of the disk is reduced. A shroud for smoothing is provided so as to surround the outer periphery of the disk, and the shroud is provided with an opening at a portion corresponding to the movement operation of the carriage, and a shroud auxiliary portion covering the opening is provided in a circumferential direction of the disk. The magnetic disk drive is formed along the shroud and attached to the shroud, and the shroud assisting portion has a comb-tooth shape having a gap in which the carriage can be inserted and moved.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A magnetic disk drive according to a first embodiment of the present invention will be described below with reference to FIGS. Here, 10 is a shroud, 12 is a shroud opening, 15 and 16 are disks, 17 is a disk spacer, 18 is a spindle, 21 is a shroud inner diameter surface, 22
Is a projection on the inner surface of the shroud, 31 is a carriage arm,
Reference numeral 32 denotes a head suspension.

First, a schematic aspect of disk flutter and power consumption in a magnetic disk device will be described.
4 and 5 show that reducing the distance between the outer peripheral surface of the disk and the shroud, that is, the shroud gap, has a reducing effect on the flutter amplitude and power consumption of the disk.

FIG. 4 shows a 2.5 "disk with 12,000 disks.
It is the result of measuring the relationship between the gap (shroud gap) between the shroud and the disk when rotating at rpm, and the flutter amplitude of the outermost periphery of the uppermost disk. From these results, it is understood that the flutter amplitude can be reduced by reducing the shroud gap.

FIG. 5 shows a 2.5 inch disk having a wide shroud gap (0.8 mm) and a narrow shroud gap (0.4 mm).
(mm) is a result of measuring a difference in power consumption while changing the number of rotations. From this result, it can be seen that the power consumption is smaller when the shroud gap is smaller.

The above results show that it is better to reduce the gap between the disk and the shroud. The current shroud gap is a minimum value of about 0.7 mm. However, in order to further reduce this, there is a problem that the assembly accuracy between the spindle and the disk drive housing must be increased.

In order to solve this problem, the first embodiment of the present invention employs a configuration in which a convex portion is provided on the inner surface of the shroud, and the convex portion is located between the disks to fill a gap between the disk and the shroud. Is what you do. FIG. 1 shows a configuration according to a first embodiment of the present invention. In FIG. 1, 10
Indicates a shroud. On the inner surface 21 of the shroud 10,
A comb-shaped convex portion 22 is provided. If you do this,
The same effect as when the gap between the disk and the shroud is reduced is obtained.

FIG. 2 is a sectional view showing a case where the shroud of FIG. 1 is mounted on a disk spindle. In FIG. 2, disks 15 and 16 are disks, and a space between the disks 15 and 16 is closed by a convex portion 22 provided on the shroud 10. In FIG. 2, the convex portions 22 are in a state of being inserted between the disks. In this manner, as shown in FIG. As a result, the generation area of the fluid force 30 can be suppressed to the inner peripheral side, and the effect of reducing the fluid force can be increased.

More specifically, as shown in FIG. 12, in the conventional shroud structure, the flow of air that jumps out of the disk due to the rotational centrifugal force of the disk meanders between the shroud wall and the turbulent air flow. Causes flutter due to the difference between the upper and lower vibrating forces applied to the disk.However, since the air flow is less turbulent on the middle to inner circumferences of the disk than on the outer circumference, The disk flutter due to the air flow on the middle to inner circumferences is not so large.

Therefore, according to the configuration of the first embodiment, since the convex portion 22 is inserted into the disk over substantially the entire circumference of the disk, the flow of air that jumps out of the disk by the convex portion is made. And the meandering air flow as shown in FIG. 12 is not generated, and the air between the disks flows substantially along the circumference of each diameter of the disk, and the outermost circumference of the flow is a convex portion. Is the peripheral surface formed by the inner edge of Therefore, the air flow between the disks is generated in the portion of the disk diameter having a length obtained by subtracting the length of the convex portion overlapping the disk from the actual disk diameter, which means that the disk diameter is effectively reduced. It is.

In the case of the first embodiment, since the projection of the shroud is inserted between the disks, it is necessary to devise a method of mounting the disk and the shroud. Therefore, as shown in FIG. 1, the shroud may be formed into a split mold that is divided substantially in half, and two shrouds may be assembled so as to cover the outer periphery of the disk. If you do this. The convex part of the shroud can be formed by a mold, and the processing becomes easy.

FIG. 6 shows a prototype of the shroud shown in FIG.
This is a result of measuring the flutter amplitude of a 5-inch, 7200 rpm disk. For comparison, the flutter amplitude when a conventional shroud of a cylindrical type is used is also shown.
The flutter amplitude was measured at the outer circumference and middle circumference of the uppermost disk using a laser Doppler vibrometer.

From the results of FIG. 6, the flutter amplitude when the comb-shaped shroud is used is about 50% of the flutter amplitude when the normal shroud is used, and the flutter reduction effect by the shroud of FIG. 1 can be confirmed. Was. The effect of reducing the flutter amplitude is related to the length of the comb teeth, and it is expected that the longer the comb teeth, the greater the effect. (Since the air flow due to the rotation of the disc occurs between the discs excluding the comb teeth, The longer the comb teeth, the smaller the diameter at which the air flow occurs, and accordingly the smaller the flutter amplitude naturally. As in this experiment, even if the comb tooth length is 4 mm, a sufficient effect is obtained. If the comb tooth length is about this length, casting is possible and suitable for mass production.

The effect of the present embodiment is obtained by reducing the radius of the flow between the disks caused by the rotation of the disk over the entire circumferential direction, and is substantially the same as reducing the disk diameter. This is effective not only for reducing the flutter amplitude but also for reducing power consumption.

Although it is known that a conventional plate-shaped current plate of a rectangular plate is inserted between the disks, there is a flutter reduction effect. However, since the current plate is placed in the air flow (the present invention). In this case, since the comb teeth extend over substantially the entire circumference of the disk, no air flow is generated between the disks corresponding to the comb teeth due to the rotation of the disk.) However, there is a problem in that power consumption increases.

The present invention also provides a squeeze effect (a high air film rigidity is generated when the gap between the two is very small, as in the case of the relationship between the rotating disk and the flying head, thereby restraining the vibration of the flying head. In contrast to the method using a known effect (eg, a known effect such as the shrinking), the gap between the disk and the comb teeth (provided on the shroud) may be large. Normally, the squeeze effect occurs in the case of a narrow gap of about several tens of μm. However, such a narrow gap poses problems of assembly accuracy and disk deflection due to impact force. Since the present invention is a method for suppressing the range of generation of a rigid flow due to the rotation of the disk, the gap between the disk and the comb teeth may be about several hundred μm, and the above-mentioned problem is not related.

Further, since a static pressure acts between the disc and the comb teeth, there is no problem that dust enters the gap due to the rotation of the disc and accumulates.

Next, a magnetic disk drive according to a second embodiment of the present invention will be described below with reference to FIGS. 9 is another embodiment for reducing a fluid force generated by a disk rotation.

Although it has already been described that the turbulence of the fluid caused by the rotation of the disk has a large effect on the outer peripheral portion, the effect of the shroud opening cannot be ignored. The shroud opening is essential for inserting the carriage arm, but having an opening in the shroud increases fluid turbulence. FIG. 7 shows the result of measuring the effect of the size of the opening.

FIG. 7 shows the result of measuring the relationship between the angle of the shroud opening and the disk flutter. As can be seen from FIG. 7, when the angle of the opening is 0, that is, when there is no opening, the flutter amplitude is small. Therefore, by covering the shroud opening so as not to hinder the operation of the carriage, the disturbance of the fluid force can be further reduced.

FIG. 8 is a second embodiment of the present invention using a shroud component that covers the shroud opening. In FIG. 8, the shroud 10 is provided with an opening 12 for inserting a carriage 31. The opening 12 has a sheet-metal-shaped shroud component 4 that covers the disk circumferential direction.
0 is provided. The shroud part is attached to the mounting portion 42.
Is fixed to the shroud by the screw 43.

FIG. 9 shows the shape of the shroud component 40. The portion covering the shroud opening is a comb tooth 41, and the gap between the comb teeth is a space where the carriage arm 31 moves. FIG. 10 shows the relationship between the shroud component and the disk in the height direction. The comb teeth 41 of the shroud part 40 are substantially at the same height as the surface on which the disk 15 is present, and the gap between the comb teeth 41 is substantially the same as the carriage arm 31.

At this time, a method of assembling such a shroud component becomes a problem. In the present embodiment, the following is performed. In FIG. 8, the shroud component 40 is mounted after the disk, carriage, etc. have been assembled. The shroud component 40 is inserted using a gap between the disk 15 and the shroud 10 on the side of the carriage arm, and is slid toward the carriage arm to cover the shroud opening. After the shroud component 40 has been positioned, it may be fixed with screws. The area 45 where the shroud component 40 is slid
The above assembling work becomes easy if it is formed on the inner surface of the.

As described above, the embodiment of the present invention includes the following configurations and those having the functions and functions.

A projection is provided on the inner surface of the shroud for insertion between the disks. As a result, the size of the space between the disks can be reduced, and the area where the swirling fluid force generated by the rotation of the disks can be reduced.

Further, as another embodiment, a shroud component that covers the circumferential direction is provided at the opening in order to make the shroud have a full circumference in a pseudo manner. In a magnetic disk drive, an opening must be provided in the shroud for inserting the carriage arm, but the presence of the opening increases fluid turbulence. It is important to make the shroud full circumference in order to realize a flow without turbulence. Therefore, in order to make the shroud full circumference, a comb-shaped shroud part is attached to the shroud opening. The area in which the carriage arm strokes utilizes the gap between the comb teeth.

[0037]

According to the present invention, it is possible to reduce the fluid force generated by the rotation of the disk, reduce the disk flutter and the power consumption increased by the rotation flow, and realize high-precision positioning and low power consumption. The effect can be achieved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a structure of a shroud in a magnetic disk drive according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of the shroud of FIG.

FIG. 3 is a plan view of the shroud of FIG. 1;

FIG. 4 is a diagram showing a relationship between a shroud gap and flutter amplitude.

FIG. 5 is a diagram illustrating an effect on power consumption by reducing a shroud gap.

FIG. 6 is a diagram showing a comparison of flutter amplitude between a comb tooth shroud and a conventional shroud of a conventional example.

FIG. 7 is a diagram illustrating a relationship between a size (angle) of a shroud opening and a flutter amplitude in a magnetic disk drive according to a second embodiment of the present invention.

FIG. 8 is a diagram showing a configuration for making a shroud extend all around in the second embodiment.

FIG. 9 is a structural diagram of a shroud component covering a shroud opening.

FIG. 10 is a diagram showing a positional relationship with a disk height in FIG. 9;

FIG. 11 is a view showing a shroud of a magnetic disk device according to the related art.

FIG. 12 is an explanatory diagram showing a flow of air between disks in a conventional magnetic disk device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Shroud 12 Shroud opening 15 Disk 17 Disk spacer 18 Spindle 21 Shroud inner diameter surface 22 Convex portion of shroud inner diameter surface 31 Carriage arm 32 Head suspension 33 Voice coil motor 40 Shroud part 41 Comb tooth 42 Shroud part mounting part

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Osamu Beppu 2880 Kozu, Odawara-shi, Kanagawa Prefecture Storage Systems Division, Hitachi, Ltd. Inside the mechanical laboratory

Claims (3)

[Claims] 1. A magnetic disk device comprising: a plurality of disks as information media; a spindle motor for rotating the disk; a head for recording and reproducing information on the disk; and a carriage for supporting the head. A shroud for smoothing the air flow in the circumferential direction of the disk caused by the rotation of the disk is provided so as to surround the outer periphery of the disk. A magnetic disk device, which is inserted between the disks so as to enter inside from the outermost periphery. 2. A magnetic disk drive comprising: a plurality of disks as information media; a spindle motor for rotating the disk; a head for recording and reproducing information on the disk; and a carriage for supporting the head. A shroud for smoothing the air flow in the disk circumferential direction caused by the rotation of the disk is provided so as to surround the outer periphery of the disk. The shroud has an opening at a portion corresponding to the movement operation of the carriage, and A shroud assisting portion covering the portion is formed along the circumferential direction of the disk and attached to the shroud, wherein the shroud assisting portion has a comb tooth shape having a gap through which the carriage can be inserted and moved. Magnetic disk device. 3. The magnetic disk drive according to claim 1, wherein the shroud has an opening in a portion corresponding to the movement of the carriage, and a shroud assisting portion that covers the opening is provided in a circumferential direction of the disk. The magnetic disk device is characterized in that the shroud assisting portion has a comb-tooth shape having a gap in which the carriage can be inserted and moved.